Talk:de Havilland Goblin
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[edit ]When the author claims that this was the second sort of engine to fly, what does s/he mean?
- It means that it was the second British engine to take to the air powering an aeroplane (the first being the Whittle Unit used in the Gloster E.28/39} as opposed to ground runs on a testbed. This is significant in that it means the engine has reached a stage in development where it has proven both powerful and reliable enough to risk the possible loss of a pilot and aircraft.
- Later engines were tested on modified airliners/bombers such as the Lancastrian and Lincoln (as well as in the tail of modified Vickers Wellingtons) and as these were multi-engine aircraft the risk of engine failure of the test jet engine was of much less consequence. Ian Dunster (talk) 10:36, 13 April 2008 (UTC) [reply ]
- Basically it means the Goblin passed an Air Ministry (AM) Type Test of 25 hours running without failure or other problems.
- 25 hours running of a new engine design was the minimum hours required by the AM for a legal manned aircraft test flight. The engine would then have to pass an additional Type Test of 150 hours before entry into RAF service. The Type Test system was a basic gauge of overall engine reliability/dependability and maintenance needs - the longer the period the less often maintenance/overhaul is needed. — Preceding unsigned comment added by 95.148.220.131 (talk) 10:42, 7 September 2015 (UTC) [reply ]
- The Power Jets W.1A was given an Air Ministry 'Special' 10 hour Type Test for the initial flight of the Gloster E.28/39. — Preceding unsigned comment added by 95.150.10.169 (talk) 09:06, 5 May 2016 (UTC) [reply ]
Specific fuel consumption units.
[edit ]It's bad enough that we still have to put up with non-SI units, but what in heavens name is lbf/lb/hr meant to be? To me that means (lbf.hr)/lb, which would then make it the reciprocal of the SFC unit as defined within the Specific Fuel Consumption article itself, namely lb/(h·lbf),(which this article links to when giving its figure). So what is the figure given here, SFC or 1/SFC?1812ahill (talk) 16:51, 27 February 2012 (UTC) [reply ]
- From the quoted unit, I'd agree with you - it's 1/SFC (i.e. less is better)
- I don't know where this uncited figure came from. My copy of Smith is the 1944 edition and it's not in there. I wouldn't like to guess if this should 1.3 or 1/1.3, but this lbf/lb/hr was certainly used as a contemporary unit of thrust/fuel. Maybe the Flight online archive and their annual engine show roundup would have a figure? Andy Dingley (talk) 17:26, 27 February 2012 (UTC) [reply ]
- I dunno:) I think you're probably more of an expert in this field than I am. Just glad I never had to deal with lbs,inches,dynes,gallons etc. I see there isn't even a consistency between use of h and hr.1812ahill (talk) 02:33, 4 March 2012 (UTC) [reply ]
- lbf/lb/hr - it just means pounds of thrust given by the engine, per pound of fuel burnt, per hour. — Preceding unsigned comment added by 80.4.57.101 (talk) 13:03, 18 March 2012 (UTC) [reply ]
- Article here: Thrust specific fuel consumption